Trucks built on the basis of a very strong structure of the chassis type, especially freight trucks such as high tonnage trucks, are very well known. The structure of said trucks comprises a rigid axle or axles mounted at the back and a front axle or axles mounted at the front, wherein front wheels turn about two vertical shafts located at the front axle ends of the truck.
In applications of trucks over 100 tons it is not possible to use a double axle or back cross-member due to their huge gross weight that prevents lateral gliding of the tires in the double cross-member when taking curves; this makes driving on curves unsafe because the vehicle tends to move on in a straight direction. For this reason, in this area the prior art makes use of only six tires per vehicle, two on the front axle and four on the rear axle, limiting its payload capacity.
Trucks in the prior art are equipped with electric motors or other types of motors only on the back wheels as it is unfeasible to mount electric motors or motors of other types on the front wheels of the freight vehicle with the steering systems known, limiting in this way its power and consequently, its payload capacity.
The maximum capacity obtained in freight trucks of the prior art is limited by the maximum weight that may be carried by the tires provided in the state of the art, and by the power that may be transmitted by the power and traction systems developed to the present date. The maximum payload a high tonnage truck may carry is given by the equation: Maximum tire and power system capacity (gvw) minus Empty weight of the truck or tare (evw). The truck with the greatest payload efficiency is that with the highest (gvw−evw)/evw ratio.
The maximum payload capacity offered by the state of the art is that of a truck of the following characteristics:                gvw=568 tons.        evw=228 tons.        load=gvw−evw=340 tons.        (gvw−evw)/evw=1.49.        
Thus, there is still in the area a need of freight trucks, and more particularly, of lighter high-tonnage freight trucks equipped with a more powerful system, that are more efficient, and that may be used for off-road applications; they must also be provided of a greater number of tires in order to improve the payload capacity and lower the cost per hauled ton. For this reason, lighter power and traction systems are needed to reduce transportation costs while preserving the safety and maneuverability levels of the freight truck.
The truck of the present invention manages to avoid all the above mentioned disadvantages with the replacement of the traditional chassis system for a knuckle joined lightweight, frameless power and traction system.
In this area there is also a need for a dump tipping system that allows to carry out a quicker and more efficient dumping of the materials in freight trucks, and avoids the traditional problems associated with dumping such as having to move from the lane followed during transport to another, forcing the operator to drive in reverse in order to dump the transported load from the back of the truck.
Finally, it is necessary to have lightweight dump bodies that increase payload capacity and allow the implementation of said tipping system. The lightweight curved dump body further comprises a lightweight suspension system that efficiently allows carrying out smooth loading and dumping operations of the material carried in the lightweight curved dump.